PESE HOUPT2SULTS FOR NURSERYU-l
Utilization of Processed Garbage as a
Uulch f or Ornamentals 1967-70
Horticulture Series fl.,o. 17
AGRICULTURAL EXPERIMUENT STATION
AbURN MUNISITY
E. V. Smith, DirectorAuut17AbrnAlbmAugust 1971 Auburn, Alabama
COIUTETS
Page
Compost as a Mulch 
for Ornamentals............,o.......oo 
I
I-ulhing Perennials: 
Garden Chrysanthemums.................. 
2
Mulching Annuals: 
Petunias..
000040
.... e....o.** ..ooeoeo.*ooo 
3
M'Iulching Woody 
Ornamentals on 
the 1ighway.................... 
3
Comtpost as a Herbicidefllh............o.... 
5
Summary and Conclusions.......... 
.. ****ooo** 0-** **e*0eoes* 
12
RESEARCH RESULTS FOR NURSEPYEN
Utilization of Processed Garbage as a Mulch for Ornamentals 1967-1970
Kenneth C, Sanderson, Henry P. Orr and W. C. Martin, Jr.
INTRODUCTION
This research had as a broad objective the determination of means of
conservation and utilization of the resources contained in garbage compost.
The compost was produced from garbage after most of the metals, rags,
and large items of refuse were removed by hand or mechanical means. The
remaining material was ground in a hammer mill sprayed with sewage, and
composted in windrows.
The compost was obtained from the 1Municipal Compost Plant of the City
of Mobile, Alabama. The material was a coarse ground compost containing
large quantities of plastic,
Compost as a Mulch for Ornamentals
The use of compost as a mulch is of interest since the large quanti-
ties of material available could be readily used in park and highway plant-
ings. Homeowners use of compost mulches would probably be limited by the
appearance and odor of the mulch.
Most processed garbage composts have a dark brown color. Some contain
considerable amounts of film and rigid plastic which detracts from the
mulch's appearance. Glass is ground to a size that does not present a
problem in appearance or handling. The texture may be granular or fibrous
depending on the stage of decomposition. Compost which contains sewage
has an odor even when well composted. Odor problems with sewage-free com-
post varies with the raw materials used, the composting method and, the
length of time the material is composted
1/ Associate Professor, Professor and Instr., respectively, Dept. of Hort.,
Agr. Expt. Sta., Auburn University.
I'lulchin Pert.--2-nnials.- C-3arden a]':janthmum
Hardy or garden chrysanthemums (ChrysanthemmmorifoliumRamat,)_
were used to test compost as a mulch for the growth of a perennial. 
On
June 21, rooted cuttings of 19 cultivars of garden chrysanthemums were
potted in 3 cm peat pots containing equal parts of soil peat and perlite
amended with 160 g superphosphate per bu. Plants were grown in the green-
house until July 13, wh-, ,en they were transplanted outside into beds at a
spacing of 38 cm x 46 cm. Plants were fertilized in the greenhouse each
week by watering with a solution containing1.9 g of 20-20-20 fertilizer
per liter of water, Fertilization in the beds consister of 146 g. o.'- 3-3
fertilizer 1 m
2 
prior to planting and monthly applications thereafter at
the same--rate. A. plants were pinched three times to increase flower
number and growth habit. Pinci4 ng w vias done on June 20, July 18, and August
15.
Each bed contained one cultivar and was divided into three sections
with 10 cm aluminum lawn edging. A 2.5 cmmlch was applied to each section
uts Ing the various mulches. Three mulch trIeatmrents used were compost,
sawdust, and pi-ne strenw. Comparisons wyere made on each cultivar in each
mulch regardingy flower'ing date, hei.ght, arid spread of plants.,
The growth ofr plants was excellent under all mulch treatments. Leaf
and flower color were comparable. H~o leae diffcrencesware noted in
flowering date, heigrht, and spread of the plants when grown in
3
11ku14zilchina Annuals: Petunias
F ifty-f our petunia (Petunia hyvbrida Vil) cultivars were planted i n a
mulIching study on annguals. T.1he petunias were produced in the greenhouse
by sowing seed in February and transplanting in -larch to peat pots contain-
ing ecual parts of soil, peat, and perlite amended with 160 g dolomite and
'0 g superphosphate per bu. Plants were Lertiliz ed the greenhouse each
week by wateringy with a solution containing 1.9 of 20-20-20 fertilizer
per liter of water.. Plants were planted in beds on April 16.
2
Fertilization consisted of 146 S of 8-3-G fertilizer per 1 m of sur-
face incorporated prior to planting and 146 a of 12w-6 fertilizer per 1 m 
2
of bed. Each plot wvas divided into three sections with 10 cm aluminum
lawFn edging. The mulch treatments consisted of counpost, sawdust, and pine
strawy applied to the section in each plot. Appro":iiately 5 cm of mulching
material w7as applied on Ulay 2.
Uo apparent differences were observed amotig mulches in the grow7thand
flowering of the petunias with any of the mulches* Leaf and flower color
was comparable in all mulch treatments.
I~julchinn, ..Yoody Ornamentals on the I'ighwa
'The establishment, maintenance, and care of-E plants on highwayeys has
become a problem because of the increased use of plants on the highlway
f or esthetic and safety reasons. Uu1lches can assist in this problem by
conserving mtoisture, reducing weeds, preventing wT.Iide f luctuatIons ifn soil
4
to a depth of 15 cm prior to planting of potted Ilex and Forsy A. The
mulches were rem.oved the second year and reapplied with the exception o
t urf fiber. Pl 1a nts wrwe watered iirnediately after planting and dring
exftreme dry spells. Iertilization consisted ef a yearly application of
15 g of dry 8-8-8 fertilizer sprinkled over the drip line of each plant.
Soil moisture and temperature readings were taken May through August. flois-
ture readings were made with ypsum block-s, located in the center of each
m.,iulch treatment at a depth of 15 cm. A telethermometer was used to read
the soil temperature as measured by thermister probes located in the center
of each mulch plot.
Soil samples were taken from the plots during June of the first year
to determine the influence of the mulches on soil nutrition. Soil samples
were analyzed for pl., phosphorus, potassium, calciu, and magnesiuv.
Differences wx-ere observed in erosion of the various mulches on the slope
which was quite steep, approimately 40 to 60degrees. Turffiber mulches
were washed or completely blown awyay before the end of the first year
and were notreplaced. Saw~sf atf'-sswcoe
and ~ ~ ;. wee'o-rpad&Swdust mlches wa--shed considerably, with large
g-ullies developing -in the Ymulch. Pecan. hulls w,,ere quite resistant to ero-"
sion, however small picces of shell did wash. 'J2o minimize eros-ion., pecan
hulls should be coarse aind not ground. Pecan h1-ulls often cakl-,ed into
LuMP s which were -Undesirable in appearance and may have impeded water pe-
netration. Compost mul..ches exhibited little if any erosion. Rigid and
Cpmiipared to no mulch, soil moisture was greater under allmulched
sites, Table 1. Soil nullched with pecan hulls had the highest meaper
cent moisture, Lower moisture was observed where pine straw, processed
garbage, sawdust, and turf-fiber were used. The slope site had a higher
miean moisture reading than the fi~at site. The proximity of water near
soil
the slope and differences in/type might exSplain these moisture differences.
iluching had no e-ffect on the mean soil temperature, Table 2.
Compost mulches raised the pH of the soil almost an entire unit above
some of the other maulch treatments, Table 3. In comparison to compost,
the other mulches did not influence soil pHT.
Compost mulches increased the amount of phosphorus, potassium,
calcium, and magnesiutm in the soil, Table 4, Soil phosphorus was reduced
by the sawdust mulchies. Soil potassium was reduced by the sawciudt, turf-
fiber, and pinestraw.-Y mulches.
Compost as a Herbicide lulch
Compost and sawdust were compared, as mulches with and without dich-
lobenil (2,6-diclillorobenzonitrite) herbicide icornoration on nursery
liner production.
Potted liners were planted at the Horticultural farm during July,
1963 in soil bins which contained 125 sq. ft. per bin. The soil in each
bin was prepared by adding G6 cu. ft. of peat moss, 5 1b. of 8003-3u ferti-
lizer and 3.5 lb. of dolomaitic limestone prior to rototilling. Test
application, all weeds were removed by hand.
Table 1. Influence of Various Muli-ches on Per Cent Available
ioui-ein the Soil ac:t 7Two Highway Sites 1/----
Mulch
F lat
Site 2/
0lope 'e an
Pet. Pct. PUt.
None 57.4 61.9 59o7
Turffiber 505 63.3 61.5
Pecan hulls 62.6 72.2 67.4
Pinestray 59.6 65.5 62.6
Sawdust 54#..4 63. 02 61 *9
Compost60.3 63.91 61.9
1/ IMeans for readings taken wpyeekly from July 7. 1969 to January 12, 1970.
2/ Flat and slope sites were located on the north and south sides of
1-85, respectively in Opelika, Alabmna.
Table 2. Inf luence of Variaous Mulches on Soil emperature at Two Highway
Sites 1
Site
Mul1c h 171la t Slope Me an
Checkr 66.7 63.0 67.4
Turff.'iber 66.6 63.0 67.3
Pecan hulls 67.5 68.1 67.3
Pinestrawy 67.1 67.5 67.3
Sawd us t 67.4 6?.1 60.
Compost 6G73 67.7 67.6
1Means for weekly readi-ng taken July
and slope sites were located on the
specitvely in Opelika, Alabama.
7, 1969 to January 12, 1970. Flat
north and south sides of 1-35 re-
Table 3. Influence of Various Mfulches on the Soil pH- at Two H-3ICihway Sites
----------------------OO4-----------------
Site 
I/'
M-ulch- .. n
HTone 5.36.3 6.1
Turffiber 5.7 6.2 6.0
Pecan hulls 5.6 6.2 5.9
P ine stax5.3 6.3 6.1
Sawdust 5.6 6.2 5.9
Compost 6.6 6.9 6.3
if Fat and slope sites were located on the-north and south sides of 1-05
respectively, in Opelika, Alabama.
a
Table 4. Influence* of Various Mulches on 
Phosphorus, Potassium, Calcium, and Magnesium 
i h
Soil at Two Highway Sites.
P K 
Ca Mg
Mulch Slope Flat Mean 
S lope F lat Mean S lope F lat 
Mlean Slp Fat N
Lb./A Lb/A Lb .IA Lb/A Lb./A 
Lb.Ie 1bA/ Lb./A 
Lb./A Lb/ A Lb.
None
Turf fiber
Pecan hulls
Pinestraw
sawdust
Compost
21.4
20.1
22.1
21;5
15.*9
31.5
27.0
2 6.8
26.4
27.0
24 ,1
33 .8
24,6
23.5
24.3
24.*3
20.0
32. 7
101.1
189.5
203.8
230.5
130.0
116.5
214.3
10499
121.9
216.6
115.6
103.0
211.6
95.2
105.2
223.6
88200
90 1V*
851.0
399.0
951.0
1,204.0
905.0
959.0
8 83,*0
955.0
1011.*0
1461.5
893.5
930.0
867.0
927.0
986.5
1,332.8
105.8
105.0
111.0
111.8
102.0
118.5
120.0
120.0
120.0
120.0
120.0
120,0
112.9
112.5
115.5
115.9
111.0
119.3
an
/A
Weed coverage wa- determi-iinedl o-n o Hovember 20,1963 and October 17,
1969. The number of plants surviving after establishment (transplant-
ing) was determined on Hovember 14, 1963. Soil below the treatments
was tested to determine treatment effect. on soil nutrients. Samples
were obtained in June of 1969 by removing the mulch andtaking random
core samnples throughout the plot.
Check plots, which received no mulch or herbidide, were completely
covered with weeds 3 to 4 monthlis alter the treatments were applied in
both 1963 and 1969, Table 5. The best weed control was obtained in
1963 with a 2-inch sawdust mulch, 2-inch sawdust mulch Plus 6.5 lb.
per acre of dichlobenil, I-inch compost mulch plus 6.5 lb. per-acre
of dichiobenil and 2-inch compost mulch plus 6.5 lb per acre of dich-
lobenilI. lericide mlches gave efective control o4 most broadleef
weeds for appromimately 9 months.
Higher percent age plant loss occurred with gyarbage compost mul-
ches (23'.4) itHan with saw.dut-st mulches (4.4) or no muvalch (3,). Wlhere
dichlobenil was -1. ed 13.9 per cent o-.--.thie plants died, whereas 13.9
per cent died where it was not used. The poorest plant slarvivil
was observed in plants mulched with tw,,o inches of compost plus a
dichlobenil tr2-eat-ment. Table 6.
Compost muylches increased the p!7, phosphorus and potassium levels
of the soil, Ta'ble 7. Sawudust mulches redluced the phosphorus, potas-w
9
Teable 5 JnIn:jcluence of -I, e fthI ndl TAthoUt Dichloben.I
Hierbicide Incorporat ion on T7Ied Control
Tleecl Control
Treatment 1%81969 ijean
Pct. Pct. Pct.
Ho miulch; no horbicide 100 100 100
Uo mulch; dichiobenil 4.5 Ib.IA 94 51176
Sawdust, 1 in.; no hnrbicide 23 69 46
Sawdust, I in.; no herbicide 2 45 24
Sawdust~ I in.;- dichalobernil 6.5 lb/A 30 40 3 5
Sawy dust, 2 in.; cichlobenil 6.5 lb-./A1 16 9
Com.ipost, 1 in.; no Iherbicide 17 0311-9
Compost, 1 in.; no herbicide 11 
94 53
Compost, 2 in.; dichlobenil 6.5 lb./A 0 42 21
Table 6. Influence of Mulch 
and Herbicide Tireatments 
on Plant Loss 4 M4onths 
After Applicain
Buxus harlandi
Rhododendron
obtu sum japorieum
Juniperus chinesis
'Pt ,itzer
Viburnum
burkwioodi
Ilex cornuta
Juniporus
conferta
Thuja pyramidalis
Meian
No No
m ulch
or
herbi-
cide
Pet.
7.0
I in. 2 in .
mulch
plus
dichlo-
benil
Pet.
26.7
1 in.
S aw-
dust
Pct.
0.0
2 in.
saw-
dust
Pet.
13.0
sawdust
with
diChlO
benid
Pet.
0.0
0.0 7.0 7.0 0.0 0.0
0.0 0.0 7.0 0.0 0.0
20.0
0,69
0.0
13.0
5.7
13.0
0.0
13.0
13.0
10.4
7.0 0.0 20.0
00.0 .0leo 0.0
0.0
7.0
40
0.0
20.0
4?7
0.0
0.0
2.9
sawdust
with
dieblo-
benil
Pet.
7.00
0.00
7.0
130
7.0
0.00
7.0
5e9
I in.
compost-
Pet.
66.7
;" in. 2 in.
2 in.
-compost
Pet.
73.3
compost
with
dichlo-
beni l
Pet.
46.7
13.0 33.3 13.0
0.0 20.0
40.*0
0.0
7.0
13.0
20.0
33.5
13.0
0.0
130
26.6
7.0
7303
13.0
0.0
20.0
24.7
compost
with
dichlo-
beni11--
Pct.
86.7
60.0
13.0
73.3
0.00
13.0
46*7
41.8
Dichobenil was applied at the 
rate of 45 lb./A when applied 
alone, and 6.5 lb./A wh
Mean
Pet.
32.7
13.3
5.4
29.3
3.3
3.3
15.3
14.7
._.........e.......... _
3 21
aon so oedos.so
.mwaaz _oMar
11
Th.r-ble 7. IIEffcct of Vcarious lulohes on Soil pH-7 
and Nutrient Content
anOuu = n ntauu m =A== ings M a112 
m3mu W W c = a =WVN= = n 
SMGAM10681V Maoa n
riulch and herbicidc treatment
1Uo mulIch; no herbicide
No mulch; dichiobenil 4.5 lb./A
Sawdust, 1 In.; no h-erbicide
Sawdust, 2 in. ; no herbi c 
ide
Sawdust, 1 in.; dichlobenil 
6.5 lb.IA
Srawdust, 2in.; dichiobenil 65. 
l.bIA
Compost, 1 in; no heirbici1dc
Coop o s t, 2 in.; no herbicidec
Compost, 1 in.; cichlobanil 
6.5 lb./A
Compost, 2 i;dichlobenil 6.5 
lb.IA
6.2
6.0
6.0
6.5
6.2
6.4
6.5
6.4
6.3
I
1
1
1
1
4
r
L
r
4
r
P K Ca
.57.6 116.0 4006.4
L43.0 73*4 446.4
A42.v0 63.0 3 3 2.3u
.26.0 49.6 331.2
L91.2 95.4 374.4
35.0 62.3 373.6
Z7296 113.2 431.2
256ou 151.0 439.2
239o2 109.6 409.6
263o3 107.4 436.0
Lb.o
120.0
120.0
114.0O
110.4
116.0
120.0
120.0
120.0
120.0
113.3
..4A...........
12
SUI1UATi~l AIMD COUCTILUSIONS
Scopost product oompost 
Pant of the City
of Mobile, Ai,-acm-ia was used in experimentszas a mulch for ornenentals.
This compost contained a small cmount of sewage-andwas coarsely ground.
A large amount of plastic was prominent in the compost.
Conclusions from the ezzperiments were as follows:
1. Compost was as satisfactory as other materials such as pine
strox- when used as a mulch for ornnimentals.
2. Comipost muilches raised the p'll of the soil --md increased the
raount of phosphorus, potassium, cal"ciumi and mangnesium in the
Soil.
3. Sawvdust wvas superior to compost as an h1-erbicide mulch on
nursery liners.